CPlusPlus: Make Environment::hashCode more local.

The function call itself shows in the critical path. Let's shave
off a few cycles by making it easier inlinable.

Change-Id: I14b06de27e99fa00f3be757193f2037792b18e01
Reviewed-by: Nikolai Kosjar <nikolai.kosjar@digia.com>

1 files changed, 17 insertions, 23 deletions

diff --git a/src/libs/cplusplus/PreprocessorEnvironment.cpp b/src/libs/cplusplus/PreprocessorEnvironment.cpp
index 23327dfefa..5760fbebd8 100644
--- a/src/libs/cplusplus/PreprocessorEnvironment.cpp
+++ b/src/libs/cplusplus/PreprocessorEnvironment.cpp
@@ -54,7 +54,18 @@
 
 #include <cstring>
 
-using namespace CPlusPlus;
+namespace CPlusPlus {
+
+static unsigned hashCode(const char *str, int length)
+{
+    unsigned hash_value = 0;
+
+    for (int i = 0; i < length; ++i)
+        hash_value = (hash_value << 5) - hash_value + str[i];
+
+    return hash_value;
+}
+
 
 Environment::Environment()
     : currentLine(0),
@@ -93,7 +104,8 @@ Macro *Environment::bind(const Macro &__macro)
     Q_ASSERT(! __macro.name().isEmpty());
 
     Macro *m = new Macro (__macro);
-    m->_hashcode = hashCode(m->name());
+    const QByteArray &name = m->name();
+    m->_hashcode = hashCode(name.begin(), name.size());
 
     if (++_macro_count == _allocated_macros) {
         if (! _allocated_macros)
@@ -223,7 +235,7 @@ Macro *Environment::resolve(const ByteArrayRef &name) const
     if (! _macros)
         return 0;
 
-    Macro *it = _hash[hashCode(name) % _hash_count];
+    Macro *it = _hash[hashCode(name.start(), name.size()) % _hash_count];
     for (; it; it = it->_next) {
         if (it->name() != name)
             continue;
@@ -234,26 +246,6 @@ Macro *Environment::resolve(const ByteArrayRef &name) const
     return it;
 }
 
-unsigned Environment::hashCode(const QByteArray &s)
-{
-    unsigned hash_value = 0;
-
-    for (int i = 0; i < s.size (); ++i)
-        hash_value = (hash_value << 5) - hash_value + s.at (i);
-
-    return hash_value;
-}
-
-unsigned Environment::hashCode(const ByteArrayRef &s)
-{
-    unsigned hash_value = 0;
-
-    for (int i = 0; i < s.length(); ++i)
-        hash_value = (hash_value << 5) - hash_value + s.at(i);
-
-    return hash_value;
-}
-
 void Environment::rehash()
 {
     if (_hash) {
@@ -278,3 +270,5 @@ void Environment::dump() const
         qDebug() << m->decoratedName();
     }
 }
+
+} // namespace CPlusPlus